[2][3] The company primarily produces circuit protection products (fuses) but also manufactures a variety of switches, automotive sensors and, through its subsidiary Zilog, microprocessors.

In addition to its Chicago, Illinois, world headquarters, Littelfuse has more than 40 sales, distribution, manufacturing and engineering facilities in the Americas, Europe and Asia.

[5] Sundt developed Littelfuse's first product, a small protective fuse, to regulate current in diagnostic equipment and prevent electrical failure.

[9] The company expanded its manufacturing base in the 1970s with new factories opening in Watseka, Illinois and Piedras Negras, Mexico.

[5] In 1974, the company also introduced Littelites, electronic indicator lights used in industrial and office machinery, household appliances and computers.

[5][11] Littelfuse also expanded into South America with a distribution and engineering center in São Paulo, Brazil.

[16][17][18][19][20] The company announced in November 2016 that COO Dave Heinzmann would succeed Hunter as president and CEO in January 2017.

[4] Products include: fuses and protectors, suppressors, gas discharge tubes, electronic switches, solenoids, battery management devices, and protective relays.